package te;

import java.util.ArrayList;
import java.util.Scanner;

interface GeneralStack {
	public Integer push(Integer item);
	public Integer pop(); 
	public Integer peek(); 
	public boolean empty(); 
	public int size();
	
}
class Car{
	private int id;
	private String name;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
}
class ArrayListGeneralStack implements GeneralStack {
   private ArrayList list;
   public ArrayListGeneralStack(){
   	list=new ArrayList();
   }

	public Integer push(Integer item) {
		// TODO Auto-generated method stub
		if(item==null)
		return null;
		list.add(item);
		return item;
	}

	public Pair<T> pop() {
		// TODO Auto-generated method stub
		if(list.size()==0)
		return null;
		 return list.remove(list.size()-1);
		
		 
	}

	public Integer peek() {
		// TODO Auto-generated method stub
		if(list.size()==0) return null;
		return list.get(list.size()-1);
	}

	public boolean empty() {
		// TODO Auto-generated method stub
		if(list.size()==0)
		return true;
		return false;
	}

	public int size() {
		// TODO Auto-generated method stub
		return list.size();
	}

	
	@Override
	public String toString() {
		
		return list.toString();
	}


	}



public class Main1 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
    Scanner sc=new Scanner(System.in);
    while(sc.hasNext()){
    	String x=sc.next();
    	if(x.equals("quit")){
    		break;
    	}
    	else if(x.equals("Integer")){
    		
    	}
    	else if(x.equals("Double")){
    		
    	}
    	else{
    		
    	}
    }
	}

}
